Production of fabrics from alginic materials



Patented a. 15, 1946 i 2 409 319 UNITED STATES PATENT OFFICE PRODUCTION OF FABRICS FROM ALGINIC MATERIALS John Bamber Speakman. Far Headingley, Leeds, and Norman Henry Chamberlain, Beadingley, Leeds, England, assignors to CeIoil' Limited, Maidenhead, England no Drawing. Application December 20, 1943, Serial No. 515,029. In Great Britain Oct. 1, 1942 v 6 Claims. (Cl. 8-1155) 1 1 y This application corresponds to the application but in the case of treatment with basic chromium of John Bamber Speakm Nflrmen Henry or beryllium salts removal of calcium is optional.

Chamberlain and Cefoil Limited, Serial No. In general it may be stated that calcium may 13,782/42, which was filed in Great Britain on be completely removed from fabrics made of cal- Qctober 1, 9 g cium alginate by treatment with cold, dilute acids,

h v ti comprises improvements in or such as hydrochloric acid. Sulphuric acid is not relating to the production of fabrics from alginic suitable owing to the insolubility of calcium s 1 materials. phate in water and aqueous solution, unless de- Up to the present it has been found possible lustring of the filaments is not undesirable. The to.prepare two main types of alginate rayon; (a) 10 precise conditions under which the extraction is t alkali-soluble type, such as calcium alginate, carried out will vary according to the nature and (b) alkali-resistant types such as chromium or properties of the fabric concerned. Thick, heavy, beryllium alginates and formaldehyde-treated alclosely-woven fabrics will require a more pr gmic acid, longed extraction treatment than thin, light, or

The alkali-resistant types have b n Produced y-woven material. The concentration of by conversion from alkali-soluble types, and have acid used is commonly 0.5 N, but this is by no then been woven or knitted in the usual way. means critical, and complete extraction can be Alginate rayon is, however, most easily made brought about, having due regard to time of treatand processed in the form of calc um alginate ment and quantity of acid used, by any acid soluand in certain instances it is desired to pro u tion having a pH value of less than 3.0 and which fabrics in part from calcium alginate with a new forms bl n; with calcium, to the removal of the alginate fibres f m h Strong solutions of mineral acids are not suitfabric after weaving or k it 1 from lace able, e. g. hydrochloric acid in concentrations fabrics as described in United States patent specigreater than 1.0 N since, although they extract fication Serial No. 450,01 It s nco the calcium effectively, they have a tendering in a factory to multiply unnecessarily the kinds of action on t material processed ya w c a pt s Stock material for p111" The acid solution may be circulated about or poses of manufacture. Furthermore, alka1ir through the fabric, if it be a very dense one, or sistant yar s, Particularly Chromium a ginate treatment may becarried out by simply steeping yarns and beryllium alginate yarns, are brittle the fabric in one or more changes of the acid and, therefore, are diflieult o W v into febricssolution. In all cases the'aoid treatment must be According to the pr n invention a Process followed by thorough washing in water containing f the production of alkali-resistant fabrics from no calcium ions, otherwise the fabric will recalcify alginic materials comprises the steps of first DI'O- d ringthe washing process ducing alginate rayon of alkali soluble type, then The following'js an example of t t of manufacturing fabric therefrom and thereafter moving calcium: converting the alkali soluble alginate of the fabric to alkali-resistant alginic material. In this way Example I it is possible to prepare calcium alginate rayon Sixty-six grams of dry calcium alginate fabric, or other alkali soluble alginate rayon as the stock 40 free from oil, are steeped in 3000 cc. of 0.5 N hymaterial for all purposes and, when alkali-redrochloric-acid for 15 minutes at room temperasistant fabrics are required to effect conversion ture. The acid is poured off, and the fabric to the alkali-resistant form after manufacture of washed for 4 hours in three changes of distilled the fabric. Thereafter the converted fabric can water, 5000 cc. being used for each change, The be laundered by the usual processes and if desired ash contentof the fabric is reduced from 13.0% dyed in alkaline baths without detriment. to 0.36% by this treatment.

The conversion to alkali-resistant material may The following are examples of the step of renbe effected by treatment with basic chromium or dering the fabric insoluble: ber llium salts, or with formaldehyde.

V V hen the alkali soluble alglnate rayon con- Example H sists of calcium alginate the calcium may be first The treatment of this example may be app ed removed for combination with alginic acid by either with or without prior removal of calcium treatment with acid and thereafter the fabric as indicated in Example I. is treated (a) with basic chromium or beryllium Basic beryllium acetate solution is prepared by salt, or (b) with formaldehyde, or (c) with both dissolving beryllium carbonate in one half of the basic chromium or beryllium salts and with quantity of acetic acid theoretically required to formaldehyde. form the normal acetate, boiling the solution to It will be understood that in the case of treatexpel carbon dioxide, and diluting the resulting ment with formaldehyde, the treatment may only liquid until it contains 5% (w./v.) of basic berylbe applied after the calcium has been removed, lium acetate.

Calcium alginate fabric is extracted with hydrochloric acid and washed in the manner already described, and is then, without drying, treated for 15 minutes or upwards at room temperature with the basic beryllium acetate solution using a fabric-liquor ratio of 100:1 followed by further washing and drying. Fabric so treated contains approximately 5% beryllium and is resistant to alkaline solutions from pH 12 downwards.

Alternatively, the calcium alginate may be treated directly with the basic beryllium acetate solution, without prior removal of calcium. In this case it is preferable to dilute the acetate solution to 2% concentration, and treat the fabric with several successive changes of this diluted solution. The take-up of beryllium is slower and less complete in this case, but satisfactory alkali-resistant materials can be prepared by this method.

Example III The following is an example of the treatment of alginate fabric with basic chromium salts. The general lines of treatment are identical with those described above with basic beryllium salts.

Two hundred grams chrome alum are dissolved in 1500 cc. of cold water, and 31.8 g. anhydrous sodium carbonate in 400 cc. cold water. The two solutions are mixed with constant stirring, and when effervescence of carbon dioxide has ceased, the liquid is made up to 2000 cc., to give a stock solution of basic chromium sulphate containing approximately 2 g. chromium per 100 cc.

Fifty grams of alginate fabric are placed in 1200 cc. water, and 300 cc. of the stock basic chromium sulphate solution is run in, with constant stirring. Treatment is allowed to proceed at room temperature for 3 /2-4 hours, with occasional agitation, after which the material is washed in running water until free from soluble chromium salts, and dried. The resulting material contains 34% chromium, calculated on the dry weight of the fabric, and is satisfactorily resistant to alkalis.

The treatment with basic chromium sulphate solution may follow extraction with hydrochloric acid for removal of calcium as already described.

Example IV The following is an example of the treatment of alginate fabric with formaldehyde.

When calcium alginate fabricsare to be treated with formaldehyde for the purpose of rendering them resistant to alkalis, it is always necessary to extract the calcium first by the methods already described.

The extracted and washed fabric is steeped for 30 minutes at room temperature in a solution containing 20% formaldehyde and 5% of ammonium chloride, the pH of the solution being adjusted to approximately 3.5 (working limits, 3.0-4.0; certainly not greater than 4.0). After steeping, the surplus liquid is removed by squeezing, and the fabric at once transferred to an oven at 98 C. for 90 minutes or longer. The material so treated is satisfactorily resistant to alkalis.

Example V The following is an example of the treatment of alginate fabrics with formaldehyde in vapour form.

The calcium alginate fabric is extracted with hydrochloric acid to remove calcium, washed, and

dried. It is then suspended in a chamber heated to approximately 100 C. by a steam jacket or other suitable means. Formaldehyde vapour is obtained by heating para-formaldehyde, either in the main chamber itself, or in a subsidiary compartment so arranged that the vapour evolved passes into the main chamber containing the fabric. In the latter case, the vapours are preferably dried by passing them over trays of anhydrous calcium chloride. Alternatively, calcium chloride, may be placed on shelves or trays in the main chamber.

Material so treated for 1 hour shows an extremely high resistance to alkalis, and its strength is considerably increased, particularly in the wet state.

Since the reaction which proceeds during the treatment of extracted alglnate fabrics with formaldehyde consists in the formation of methylene bridges between adjacent hydroxyl groups of the mannuronic acid residue chains, the carboxyl groups of the structure are unaffected, and are therefore available in the formaldehydetreated material for subsequent combination with basic beryllium or chromium salts. It is therefore clear that any or all of the treatments with basic beryllium or chromium salts already detailed may be applied equally well to material which has already been treated with formaldehyde either in liquid or gaseous form. While such double treatment would not normally be necessary in order to confer adequate alkaliresistance, it might upon occasion be necessary in cases where the utmost resistance to alkaline solutions was required.

The treatments described are equally applicable to knitted and woven fabrics, and to fabrics consisting of calcium alginate in combination with other textile materials such as cotton, wool, viscose or casein fibre.

We claim:

1. A process for the production of alkali-resistant fabrics from alginic materials, comprising the steps of first producing alginate rayon of alkali soluble type, then manufacturing fabric therefrom and thereafter convertin the alkali soluble alginate of the fabric to alkali-resistant alginic material.

2. A process as claimed in claim 1, wherein the I conversion to alkali-resistant material is effected by treatment with basic salts of metals selected from the class consisting of chromium and beryllium.

3. A process as claimed in claim 1, wherein conversion to alkali resistant material is effected by treatment with dilute basic beryllium acetate solution.

4. A process as claimed in claim 1, wherein the conversion to alkali-resistant material is effected by treatment with dilute basic chromium sulphate solution.

5. A process for the production of alkali-resistant fabrics from alginic materials, comprising the steps of first producing calcium alginate rayon, then manufacturing fabric therefrom, thereafter removing the calcium from the fabric by treatment with acid and thereupon treating the fabric with formaldehyde.

6. A process as claimed in claim 5, wherein the extraction of calcium from the rayon in the fabric is effected by treatment with hydrochloric acid.

JOHN BAMBER SPEAKMAN. NORMAN HENRY CHAMBERLAIN. 

